methods used to extract fragrant oils today are based
on the ancient principles of maceration, expression
and stream distillation. An "absolute" is
an extract obtained by extraction with volatile solvents
or by enfleurage. It is considered the purest perfume
material, retaining most of the plant's aromatic constituents.
Many modern techniques stem from those of ancient cultures.
et maceration This
technique is very costly, and is rarely used
today. It reached its peak in 1860 and made
the reputation of Grasse. It is a labor-intensive
process that yields the highest quality of absolutes
because it does not involve heat. Heat always
alters the fragrance. It is used on delicate
flowers that can not stand up to the high heat,
and that continue to release essential oils
after they have been picked. Examples of these
flowers are Jasmine, Violet, Tuberose and Rose.
goes back thousands of years to the ancient Egyptians.
It works on the principle that fats absorb smells.
Petals or other fragrant parts of a plant are
steeped in fat or non-evaporating oil which will
absorb their fragrance. A mixture of pork, lard
and beef suet are smeared on to a glass plate
in a wooden frame called a chassis. The flowers
are placed on the fat and left to release their
oils for several days. This process was repeated
several times with fresh flower heads until the
fat was totally absorbed with essential oil, the
resultant substance being known as 'pomade'; the
oil was then retrieved from the fat by dissolving
in an alcoholic solvent. This is mechanically
mixed with alcohol for up to one week, and is
chilled to -68 degrees F. The essential oils dissolve
in the alcohol and the fat does not. The mixture
is chilled and filtered several times to remove
all the fat. The alcohol is then evaporated to
leave the pure absolute. Sometimes enfleurage
is now carried out with cloth soaked in olive
oil or liquid paraffin, which is laid over the
frames instead of fat, the resultant perfumed
oil being then known as 'huile antique'.
is similar to enfleurage. Maceration is used to
extract essential oils from animal ingredients,
vanilla and iris. These materials are steeped
into vats of oil until the scented parts dissolve.
The oil may be heated to speed up the process.
Maceration takes long periods of time (sometimes
is a simple technique where the rinds of citrus
fruits are cold pressed to extract their essential
oils using rollers or sponges. There is no heat
involved, leaving the oil to smell very close
to the original plant. The ancient Egyptians gathered
flowers in a cloth bag which was twisted until
the oil dripped out. In Italy, lemon oil is also
occasionally expressed by a process called ecuelle.
Distillation Distillation is the main method used
for extracting essential oils. Distillation is
based on the principal that when plant material
is placed in boiling water, the essential oil
in it will evaporate with the steam. Once the
steam and oil have been condensed, the oil will
separate from the water, and it can be collected.
Plants are crushed to encourage them to release
their oils. Plants are boiled in water, and the
essential oils vaporize and rise up with the steam.
The vapors are captured, and allowed to condense
back into liquids. The essential oils are poured
into Florentine flasks. Five to six tons of roses
are needed to obtain one kilo of essential oil.
Current methods also involve placing the plants
on a screen and steam is passed through them.
with volatiles solvents This
method is used for delicate flowers whose odors
are damaged by the high heat needed to boil water.
The oils are extracted using solvents which have
lower boiling points than water. Various substances
such as ether or high-grade petroleum, which evaporate
rapidly, are used in modern perfumery to dissolve
essential oils from fragrant plant and animal
materials. The usual method involves placing the
fragrant material on perforated metal plates in
a container (the extractor); the solvent is passed
over them and led into a still, where it evaporates,
leaving a semi-solid mass known as concrete, which
contains the essential oil together with stearoptene.
The oil can then be separated from the stearoptene
by extraction with alcohol in a 'batteuse', producing
the substance called absolute, which is the purest
and most concentrated form of essential oil known.
part from these techniques there are various other
operations such as rectification, fractional distillation,
terpenes removal, decolourisation, etc., which
improve and refine the numerous raw materials
used for the blending and making of perfumes.